350 EDWAKD S. MORSE ON 



In life, the pallinin in the Lingulidae exhibits on its inner surface and around its 

 borders a rich brown pigmentation. In the anterior portion of the pallium, this pigmenta- 

 tion assumes a definite color pattern. It is possible that these markings may offer charac- 

 ters for specific determination, though they would have to be made out fi-om living- 

 specimens, as in alcohol these colors entirely disappear. The perfect symmetry of this 

 pattern on each side of a median line, the rich brown color of the design in contrast to 

 the pure white or greenish tinge of the remaining surface, with the rosy tints of the red 

 circulating fluid in the laci;nae, render the pallium a most beautiful object in life. In 

 52: 8,9,10,11, are given figures of the anterior portion of the pallium of Glottidia 

 pyramidata, Linrjida lepidula, Lingida cmatina, and Lingula sp. (Nagasaki), respectively. 

 The pattern of ornamentation is seen to l)e quite chfferent in each form though there is 

 some individual variation. In 39: 1, 3, an attempt has been made to show the color of 

 this pattern in L. lepidida. Reference has already been made under Sense Orcjans to the 

 anterior folds of the pallium, which are richly pigmented and which I have surmised to be 

 sensitive to light. The most conspicuous feature of the borders of the palhum are the 

 crowded setae which spring from setigerous follicles somewhat deeply buried in the 

 pallium. In 52: 7'^ I have indicated by a figure of Glottidia, natural size, the portion of 

 the pallium which has l^een removed and of which a greatly magnified figure is given 

 just aljove. In a rough way, the setae and a few rows of gill ampullae are shown, as well 

 as the general arrangement of muscle fibers involved in the movements of the setae, so far 

 as they could be made out with a low power. After the truly superb details of the setal 

 muscle in L. amitina given by Blochmann, it seems useless to present this drawing; 

 nevertheless an idea of the gill ampullae and setae with their general relations and color 

 patterns are fairly portrayed, and may be of some interest. 



Viewing Glottidia from the dorsal surface, a treble, gourd-like outline is distin- 

 guished, which represents the boundaries of the coelomic wall. All markings within 

 this outline are caused by the muscles, stomachal glands, genitalia, digestive tract, etc. 

 All markings outside this outline are made by the brachia and the sinuses and lacunae of 

 the pallium. 



The region enclosed by the dorsal and ventral jjallium, fore and aft and laterally, 

 communicates freely with the sea water. The treble, gourd-shaped figure may be defined 

 as follows: the anterior portion embraces the region of the dorsal attachment of the 

 lateralis muscles and the pharynx and oesophagus, and niiglit l^e called the peri-oesopha- 

 geal cavity ; the second gourd embraces the stomarli, a portion of the stomachal glands, 

 and the first and second antei'ior occlusors, ami may properly be designated as the peri- 

 gastric cavity ; the tliird and largest gourd, forming tlie main coelomic cavity, is nearly 

 circular in shape and includes the intestine, a portion of the stomachal glands, the 



